The Alcazar of Jerez de la Frontera is a former Moorish alcázar, now housing a park, in Jerez de la Frontera, Andalusia, Spain. It was declared Bien de Interés Cultural in 1931.

A first fortress was probably built in the 11th century, when Jerez was part of the petty kingdom of the taifa of Arcos de la Frontera, on a site settled since prehistoric times in the south-eastern corner of the city. In the 12th century, a new structure was erected to be used as both residence and fortress by the Almohad rulers of southern Spain. Later, after the Reconquista of Andalusia, it was the seat of the first Christian mayors.

Features include:

- a grossly quadrangular line of walls, with a perimeter of c. 4,000 m

- the Octagonal Tower, in Almohad style

- the Tower of Ponce de León (14th century), annexed to the keep.

- mosque, the only remaining of the eighteen once present in the city. After the Christian conquest of the fortress in 1261, it was put under the command of Nuño González de Lara. Later, it was turned into a church dedicated to Virgin Mary by king Alfonso X of Castile. The minaret, still extant, was turned into a bell tower. The praying hall, preceded by a small room of ritual ablutions, features a mihrab, indicating the direction of Mecca, and a rib vault with a circular window at the top.

- Palace of the Patio de Doña Blanca, dating to the 12th century Islamic structure, originally a leisure pavilion

- Baths. They include an entrance area for undressing, leading to the cold and tepid rooms, the latter being the largest in the complex. The final room is the hot room, whose heating system is still partially visible.